1. Field of the Invention
The present invention relates generally to a bowsprit or spar projecting from the bow of a sailing vessel and in particular to a retractable bowsprit for supporting a spinnaker sail or other headsail.
2. Description of the Related Art
A sailboats sails are deployed to catch the wind and provide the force for moving the boat through the water. Various sails are employed on a sailboat for different sailing conditions and different sailing directions. When sailing with the wind, or downwind, a large sail called a spinnaker may be deployed to catch the wind. The spinnaker is a sail commonly deployed off the front of the boat during downwind sailing. The spinnaker may be supported by a spinnaker pole which is a structure that is attached to the mast and used for the purpose of supporting and positioning the tack of the spinnaker in a substantially horizontal manner away from the mast. A traditional bowsprit is a structure extending from the front of the stem or bow of the boat which is used to support the tack of a jib or other headsails.
In modern sailing craft, where a bowsprit is provided, it is usually of a retractable design and mounted within the hull of the craft and extends through an opening below and to one side of the bow from which it can be extended.
Normally, a sailboat has a mainsail which is a triangular sail extending behind the mast. The mast is a spar or relatively rigid elongated pole that supports a sail in some way and is mounted extending vertically from the deck. In sloop-rigged sailboats or sloops, a triangular jib sail is also supported by the mast at the head or top most corner of the triangle. Sailboats cannot sail directly into the wind, but typically have the ability to sail within 50° or less of the true wind direction. Sailing as close to the wind as is possible is referred to as beating. Therefore, sailboats must keep tacking (changing sailing direction) when beating and end up sailing a zigzag route to a reach any point directly upwind from the starting point.
As noted, some sailboats have a bowsprit, which is a type of spar extending forward from the bow to which a jib or other headsail is attached. Many sailboats are also rigged to carry spinnakers, which are large sails for running, or sailing downwind, and reaching. Reaching refers to sailing at angles to the true wind between beating and running, or approximately from 50° to 160° from the true wind.
Spinnakers are sails that typically have an isosceles triangle shape with somewhat rounded sides. A spinnaker is stowed when a sailboat is beating and then lifted with a spinnaker halyard to place the head of the spinnaker at or near the top of the mast when reaching and running. Spinnakers have one of the lower corners attached to a forward end of a spinnaker pole. Conventionally, the aft or rear most end of the spinnaker pole is attached to the front of the mast. As shown in FIG. 11, a spinnaker carried on a spinnaker pole mounted on a mast is normally symmetrical in that lengths of the sail's port and starboard edges are equal. When the spinnaker is stowed, the spinnaker pole is either lowered to the deck or removed from the mast and stowed on the side deck.
In many newer designs, the spinnaker pole is replaced by a bowsprit which is mounted so as to project from the bow of the sailboat. This can usually be retracted along a generally horizontal path into the hull when the sailboat is not carrying the spinnaker so that the bowsprit is not left projecting from the bow where it could be damaged in a collision and may represent a potential danger to the crew of other boats crossing the bow.
As shown in FIG. 12, a spinnaker carried on a retractable bowsprit is typically asymmetrical, meaning that the triangular sail shape is scalene rather than the generally isosceles shape of a conventional spinnaker. The asymmetric spinnaker is similar to a genoa sail, but larger and with a fuller and more rounded shape. The longest edge of an asymmetrical spinnaker is typically connected between the forward end of the bowsprit and the top, or a location near the top, of the mast. The other vertical edge of an asymmetrical spinnaker is trimmed with a spinnaker sheet to a leeward point on the boat hull similar to that of a conventional spinnaker.
Although an asymmetrical spinnaker does not permit sailing an angle as “deep” or downwind as a symmetrical spinnaker design, it has the advantage of allowing faster reaching speeds than possible with symmetrical spinnaker or even with a large genoa sail. Some sailboats can sail more rapidly to a particular downwind point by reaching for a time on one jibe (or direction), and then jibing to a reach on the opposite jibe rather than by running directly downwind. Jibing refers to steering the sailboat stern through the wind from one tack to the other while sailing downwind.
Recently it has become a normal industry practice to add a bowsprit in favor of the previously common spinnaker pole. This is because of the simplicity of jibing an asymmetrical spinnaker mounted on a bowsprit, when compared with jibing a conventional symmetrical spinnaker mounted on the spinnaker pole projecting from either the port or starboard side of the mast.
Jibing a symmetrical spinnaker is difficult because the symmetrical spinnaker pole mounted on the mast must be transferred from one side of the boat to the other during a jibe. Because the spinnaker pole projects beyond the forestay of the boat, the outboard end of the pole must be detached from the tack of the sail and then reattached once the pole is moved to the opposite side of the boat. This jibing maneuver is usually accomplished by using a so-called “dip pole” jibe in larger boats, or sometimes an “end-over-end” jibe in smaller boats.
This jibing task is one of the most difficult tasks in all sailing maneuvers, especially in higher winds, and can result in the crew losing control of the boat. The spinnaker often collapses during the jibe maneuver and in high winds may even wrap itself around the forestay resulting in a very hazardous situation for the crew. Although experienced racing crews are skilled in carrying out this downwind jibing maneuver, things can go wrong during spinnaker jibes even at the highest of crew skill levels, such as in America's Cup racing.
As a result of the complexity of jibing symmetrical spinnakers mounted on spinnaker poles and the resulting requirement of high crew skill levels, many new boat designs have moved away from this in favor of the asymmetrical spinnaker mounted on an extendable bowsprit. Jibing an asymmetrical spinnaker is a much simpler maneuver because the bowsprit remains fixed in position and attached to the sail throughout the jibe, and is only marginally more difficult than jibing the much smaller jib sail.
U.S. Pat. No. 6,857,380 discloses a retractable bowsprit for a sailboat suitable for use with an asymmetrical spinnaker. A support element and a bowsprit positioner are track mounted within the hull of the sailboat to allow the bowsprit to assume either an extended or retracted position. The bowsprit positioner is mounted to the bottom of the hull. This U.S. Pat. No. 6,857,380 is incorporated herein by reference.
Such a retractable bowsprit is usually mounted to one side (usually on the starboard side) of the boat under the foredeck and at a slight angle to the fore and aft centerline of the boat. The pole is mounted in such a way that, when extended, the outboard end of the pole is exactly along the centerline of the boat and directly in front of the bow. This is done to avoid mounting the pole directly down the centerline of the boat underneath the foredeck.
Retractable bowsprits are rarely mounted along the centerline, particularly in larger craft, because such a mounting position would likely interfere with access to the interior of the forepeak or V berth, and also block access to any hatch mounted in the center of the foredeck. By mounting the pole against the side of the boat, and angling the pole with this method, the same position is achieved as if the pole was mounted down the centerline of the boat, and therefore the tack of the spinnaker is always at the centerline of the boat whether sailing on the starboard or port jibe.
However, there are significant disadvantages to this industry practice of a below-deck offset bowsprit mounting arrangement that the present retractable bowsprit invention seeks to eliminate. Firstly, and perhaps most importantly, mounting the retractable bowsprit below the deck requires a relatively large aperture to be created through the hull near the bow, in one of the worst possible positions where it is constantly receiving waves and spray when underway. This aperture is difficult, if not impossible, to completely seal and therefore may allow at least small amounts of water to enter the boat. Water can travel through the aperture in the bow then along the internal bowsprit sleeve and into the forepeak section of the boat. During long periods underway, and even when the spinnaker is not in use, water taken inboard through the aperture could build up and represents a “silent” and arguably unnecessary additional safety hazard to the boat and crew.
Secondly, mounting the retractable bowsprit offset inside the forepeak makes the hull more complex and expensive to produce. The production molds used to produce the hull must also be more complex and non-symmetrical along the centerline, increasing manufacturing costs.
Thirdly, the retraction mechanism for these bowsprits is often difficult for the user to access. Should something fail with the retraction mechanism, it may not be possible for the crew to correct the fault underway. In large sailboats with V berths, the mechanism maybe concealed behind fixed panels. In small sailboats with little or no interior space, the mechanism may be inaccessible, or may require a crew member to crawl forward into an unlighted and narrow space between the deck and hull to gain access to the mechanism.